The Korean Institute of Energy Research (KIER) announced 20.4% efficiency for a polymer substrate ultra-light flexible CIGS thin film solar cell. This it says comes close to 20.8% efficiency that Switzerland's Empa reported in July 2019 (see Empa Achieves 20.8% CIGS Flexible Solar Cell Efficiency).
"This developed technology will contribute to urban development by producing new high value-added solar cell products and creating next-generation applications fields," said Co-author and Principal Researcher Jaeho Yoon.
According to the Korean researchers, in order to achieve 20.4% efficiency their CIGS thin-film solar cell uses a new low-temperature film formation technology which helped lower the deposition temperature while maintaining efficiency since the usual CIGS deposition process involving high temperatures of about 550ºC would not suit polymer substrate that has a low melting point.
To enhance the efficiency of their lightweight and flexible high-efficiency CIGS thin-film cell on polymer substrate, the team used an external alkali incorporation technology that was included into the CIGS absorber layers.
"This achievement is evaluated as the establishment of a standard process for high efficiency of ultra-light flexible CIGS thin film solar cells. It is worthwhile to note that we have secured the original technology for Korea," said Kihwan Kim, Principal Researcher at KIER .
The team says it will further conduct research on large-area high-speed CIGS thin-film solar cell manufacturing technology and related equipment that can be installed on building walls and roofing materials.
KIER says the research results have been published in the international energy journal Nano Energy (IF: 15.548).